PCI: Use ioremap(), not phys_to_virt() for platform ROM

On some EFI systems, the video BIOS is provided by the EFI firmware.  The
boot stub code stores the physical address of the ROM image in pdev->rom.
Currently we attempt to access this pointer using phys_to_virt(), which
doesn't work with CONFIG_HIGHMEM.

On these systems, attempting to load the radeon module on a x86_32 kernel
can result in the following:

  BUG: unable to handle page fault for address: 3e8ed03c
  #PF: supervisor read access in kernel mode
  #PF: error_code(0x0000) - not-present page
  *pde = 00000000
  Oops: 0000 [#1] PREEMPT SMP
  CPU: 0 PID: 317 Comm: systemd-udevd Not tainted 5.6.0-rc3-next-20200228 #2
  Hardware name: Apple Computer, Inc. MacPro1,1/Mac-F4208DC8, BIOS     MP11.88Z.005C.B08.0707021221 07/02/07
  EIP: radeon_get_bios+0x5ed/0xe50 [radeon]
  Code: 00 00 84 c0 0f 85 12 fd ff ff c7 87 64 01 00 00 00 00 00 00 8b 47 08 8b 55 b0 e8 1e 83 e1 d6 85 c0 74 1a 8b 55 c0 85 d2 74 13 <80> 38 55 75 0e 80 78 01 aa 0f 84 a4 03 00 00 8d 74 26 00 68 dc 06
  EAX: 3e8ed03c EBX: 00000000 ECX: 3e8ed03c EDX: 00010000
  ESI: 00040000 EDI: eec04000 EBP: eef3fc60 ESP: eef3fbe0
  DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00010206
  CR0: 80050033 CR2: 3e8ed03c CR3: 2ec77000 CR4: 000006d0
  Call Trace:
   r520_init+0x26/0x240 [radeon]
   radeon_device_init+0x533/0xa50 [radeon]
   radeon_driver_load_kms+0x80/0x220 [radeon]
   drm_dev_register+0xa7/0x180 [drm]
   radeon_pci_probe+0x10f/0x1a0 [radeon]
   pci_device_probe+0xd4/0x140

Fix the issue by updating all drivers which can access a platform provided
ROM. Instead of calling the helper function pci_platform_rom() which uses
phys_to_virt(), call ioremap() directly on the pdev->rom.

radeon_read_platform_bios() previously directly accessed an __iomem
pointer. Avoid this by calling memcpy_fromio() instead of kmemdup().

pci_platform_rom() now has no remaining callers, so remove it.

Link: https://lore.kernel.org/r/20200319021623.5426-1-mikel@mikelr.com
Signed-off-by: Mikel Rychliski <mikel@mikelr.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 15 insertions, 2 deletions

diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/bios/shadowpci.c b/drivers/gpu/drm/nouveau/nvkm/subdev/bios/shadowpci.c
index 9b91da09dc5f..8d9812a51ef6 100644
--- a/drivers/gpu/drm/nouveau/nvkm/subdev/bios/shadowpci.c
+++ b/drivers/gpu/drm/nouveau/nvkm/subdev/bios/shadowpci.c
@@ -101,9 +101,13 @@ platform_init(struct nvkm_bios *bios, const char *name)
 	else
 		return ERR_PTR(-ENODEV);
 
+	if (!pdev->rom || pdev->romlen == 0)
+		return ERR_PTR(-ENODEV);
+
 	if ((priv = kmalloc(sizeof(*priv), GFP_KERNEL))) {
+		priv->size = pdev->romlen;
 		if (ret = -ENODEV,
-		    (priv->rom = pci_platform_rom(pdev, &priv->size)))
+		    (priv->rom = ioremap(pdev->rom, pdev->romlen)))
 			return priv;
 		kfree(priv);
 	}
@@ -111,11 +115,20 @@ platform_init(struct nvkm_bios *bios, const char *name)
 	return ERR_PTR(ret);
 }
 
+static void
+platform_fini(void *data)
+{
+	struct priv *priv = data;
+
+	iounmap(priv->rom);
+	kfree(priv);
+}
+
 const struct nvbios_source
 nvbios_platform = {
 	.name = "PLATFORM",
 	.init = platform_init,
-	.fini = (void(*)(void *))kfree,
+	.fini = platform_fini,
 	.read = pcirom_read,
 	.rw = true,
 };